Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond the minimal boolean annotations, the description discloses a real behavioral trait: it charges 2 credits only when a phone number is found. It also instructs callers to send an Idempotency-Key header for safe retries. It does not mention auth or rate limits, but the material side effects are covered.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no filler. The core purpose and accepted inputs are front-loaded, and the cost and idempotency guidance each earn their place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the high schema coverage and presence of an output schema, the description covers the main decisions an agent faces: which inputs are valid and what side effects to expect. It could be slightly stronger by explicitly saying to use persons_find_email when only an email address is needed, but it is otherwise complete for a lookup tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already describes each parameter well, so the baseline is 3. The description adds value by clarifying the accepted identifier alternatives and the dependency between 'name' and 'company domain' via the phrase 'full name and company domain.' This helps an agent understand valid combinations beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific action ('Find'), a concrete resource ('a person's phone number'), and the exact input routes (LinkedIn URL, email, or full name plus company domain). This clearly distinguishes the tool from siblings like persons_find_email and persons_lookup.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context: use this tool when you need a phone number and have one of the listed identifiers. It does not explicitly name alternative sibling tools or state when not to use it, but the identifier-based usage is unambiguous.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.